Vibration Of High-speed Trains Research Articles

Numerical and experimental study on adaptive stiffness yaw damper for suppressing abnormal vibration of high-speed trains

Numerical and experimental study on adaptive stiffness yaw damper for suppressing abnormal vibration of high-speed trains

Research on abnormal vibration of high-speed train based on wheel-rail coupling modal analysis

During dynamic line testing of a high-speed train, it was observed that the vehicle exhibited significant abnormal vertical vibrations under specific track conditions. The frequency of this vibration varies with the train speed and exhibits harmonics through analysis. As the speed approaches 400 km/h, the peak frequency is close to 44 Hz, corresponding to the system structure's natural frequency. A finite element model of the wheel-rail coupling was established for modal analysis, which revealed that the coupling between the bogie and the track will form a bogie P2 force resonance mode, which closely matches the frequency range of the abnormal vibrations. A dynamic model of vehicle-track rigid-flexible coupling was established, to simulate vibration reproduction and the bogie P2 force resonance mode variation law. Additionally, irregularities of specific wavelengths on the track can excite this mode, leading to a significant increase in amplitude. Some sections of the track line have slab warping, with a wavelength of approximately 2.45m. The frequency range of excitation formed when the vehicle speed approaches 400 km/h is close to that of the bogie P2 resonance mode. As a result, coupling resonance occurs between the vehicle and track systems, ultimately causing abnormal vibrations.

Parameter optimization of multi-suspended equipment to suppress carbody vibration of high-speed railway vehicles: a comparative study

ABSTRACTParameter optimization of equipment suspended under the carbody underframe is one of the important measures to suppress carbody vibration of high-speed trains. Previous work focused on using one equipment as a dynamic vibration absorber to control carbody vibration, overlooking the coupling effects of multiple equipments and their vibration tolerance. To address this, a comprehensive study involving multi-objective and multi-parameter optimization to enhance both carbody and equipment vibration performance is proposed. First, a theoretical model with one equipment is established to derive optimal parameters, and a simulation model with multi-suspended equipment is built to conduct optimize calculations with an improved niche genetic algorithm (INGA). Afterwards, a comparative study on carbody and equipment vibration performance is analysed based on the optimal parameters, proving that the optimal method with INGA is more effective in improving vehicle performance. Finally, the method is applied to a newly designed vehicle, and the performance is validated on a rig, providing technical support for the design of high-speed vehicles.

Analysis of the influence of track irregularity on high-speed train ride comfort

The vibration of high-speed trains induced by track irregularities is a main factor affecting ride comfort. Especially, the long-wavelength track irregularities can reduce the passengers’ ride comfort by increasing the vibration of the high-speed trains. A three-dimensional human body model coupled to a vehicle body and tracks is established to form a coupled human-seat-vehicle-track system for investigating the influence of the long-wavelength track irregularities on ride comfort. The parameters of the seated human model are determined by measurement based on the multi-island GA method. The coupled model is then used to evaluate the ride comfort of high-speed trains using ISO 2631 under the excitation of the track longitudinal level irregularities. The effects of primary, secondary suspension, and seat support vertical stiffness and damping on ride comfort are analysed. The results show that the track's longitudinal irregularities lead to high human body vibration levels and large ride comfort indices (lower ride comfort), especially when the irregularity excitation frequency is near the natural frequency of the high-speed train. The passengers’ ride comfort is more sensitive to the vertical secondary suspension stiffness than the other suspension parameters.

Research on Performance Degradation Estimation of Key Components of High-Speed Train Bogie Based on Multi-Task Learning

The safe and comfortable operation of high-speed trains has attracted extensive attention. With the operation of the train, the performance of high-speed train bogie components inevitably degrades and eventually leads to failures. At present, it is a common method to achieve performance degradation estimation of bogie components by processing high-speed train vibration signals and analyzing the information contained in the signals. In the face of complex signals, the usage of information theory, such as information entropy, to achieve performance degradation estimations is not satisfactory, and recent studies have more often used deep learning methods instead of traditional methods, such as information theory or signal processing, to obtain higher estimation accuracy. However, current research is more focused on the estimation for a certain component of the bogie and does not consider the bogie as a whole system to accomplish the performance degradation estimation task for several key components at the same time. In this paper, based on soft parameter sharing multi-task deep learning, a multi-task and multi-scale convolutional neural network is proposed to realize performance degradation state estimations of key components of a high-speed train bogie. Firstly, the structure takes into account the multi-scale characteristics of high-speed train vibration signals and uses a multi-scale convolution structure to better extract the key features of the signal. Secondly, considering that the vibration signal of high-speed trains contains the information of all components, the soft parameter sharing method is adopted to realize feature sharing in the depth structure and improve the utilization of information. The effectiveness and superiority of the structure proposed by the experiment is a feasible scheme for improving the performance degradation estimation of a high-speed train bogie.

Analysis of the influence of CA mortar layer void on the dynamic performance of high-speed trains

The void of cement asphalt (CA) mortar layer will aggravate the abnormal vibration of high-speed trains at the void position and threaten the running safety. Few studies have been conducted on the effect of mortar layer void on the dynamic performance of slab track on bridges and the damage limits. Aiming at the practical problem of CA mortar layer void in track-bridge systems, a dynamic response calculation program for the train-track-bridge system is prepared based on the train-track-bridge interaction theory. A sample library of high-speed trains running performance indicators considering random initial track irregularity under CA mortar layer void conditions is constructed. The influence of void length on the dynamic performance of high-speed trains under two different CA mortar layer void conditions is investigated by means of sample upper bounds based on probability guarantee rate. The results show that the wheel load reduction rate and vertical acceleration of high-speed trains are more sensitive to changes in void length than the derailment coefficient. The effect of CA mortar layer void on the running performance index of high-speed trains is significantly enhanced after a certain critical void length value, railway maintenance should pay more attention to critical thresholds. The mid-span void and beam-end void length thresholds of CA mortar layer based on the probability guarantee rate decrease significantly with the increase in running speed while utilizing the wheel load reduction rate as the control index. However, the void position has little influence on the void length threshold. The void length threshold results can provide a basis for the CA mortar void limits.

Modeling and Second-Order Sliding Mode Control for Lateral Vibration of High-Speed Train With MR Dampers

The lateral vibration of high-speed train reduces the ride stability and passenger comfort. Semi-active suspension system is often adopted to suppress the lateral vibration of trains due to its low cost and low energy consumption in control, where magnetorheological (MR) damper is the main vibration absorber. In this paper, a full model of the controlled system that consists of the 3-degree of freedom train model and the hysteretic MR damper model is first built. Then, a second-order sliding mode (SOSM) controller is designed for the suppression of lateral vibration of train, where the hysteresis and non-hysteresis nonlinearities are addressed simultaneously and rigorously. Finally, comparative simulations are conducted under the excitation of the German low-interference track spectrum. The results show that the proposed controller can suppress the lateral vibration of high-speed train efficiently in the sense that, compared with the passive control, the internal model-based resonant control and repetitive learning control, the suspension ratio of root-mean-square of lateral acceleration is reduced by 96.98%, 35.70% and 10.54%, respectively.

Cover Image

The cover image is based on the Research Article A deep learning framework for adaptive compressive sensing of high-speed train vibration responses by Si-Xin Chen et al., https://doi.org/10.1002/stc.2979

Recurrent neural network model for high-speed train vibration prediction from time series

In this article, we want to discuss the use of deep learning model to predict potential vibrations of high-speed trains. In our research, we have tested and developed deep learning model to predict potential vibrations from time series of recorded vibrations during travel. We have tested various training models, different time steps and potential error margins to examine how well we are able to predict situation on the track. Summarizing, in our article we have used the RNN-LSTM neural network model with hyperbolic tangent in hidden layers and rectified linear unit gate at the final layer in order to predict future values from the time series data. Results of our research show the our system is able to predict vibrations with Accuracy of above 99% in series of values forward.

Effect of unbalanced magnetic pull on the thermal characteristics of traction motor bearing

Purpose The purpose of this paper is to analyze the unbalanced magnetic pull (UMP) of the rotor of traction motor and the influence of the UMP on thermal characteristics of traction motor bearing. Design/methodology/approach The unbalanced magnetic pull on the rotor with different eccentricity was calculated by Fourier series expansion method. A bearing thermal analysis finite element model considering both the vibration of high-speed train caused by track irregularity and the UMP of traction motor rotor was established. The validity of the model is verified by experimental data obtained from a service high-speed train. Findings The results show that thermal failure of bearing subassemblies most likely occurs at contact area between the inner ring and rollers. The UMP of rotor of traction motor has a significant effect on the temperature of the inner ring and roller of the bearing. When the eccentricity is 10%, the temperature can even be increased by about 12°C. Therefore, the UMP of rotor of traction motor must be considered in thermal analysis of traction motor bearing. Originality/value In the thermal analysis of the bearing of the traction motor of high-speed train, the UMP of the rotor of the traction motor is considered for the first time

Sliding Mode Control of Lateral Semi-Active Suspension of High-Speed Train

A control algorithm for lateral semi-active suspension based on sliding mode observer is proposed to solve lateral vibration of high-speed trains caused by railway surface excitation. Firstly, the multi-degree-of-freedom vehicle dynamics model of high-speed train is revised on the basis of variation in spring coefficient caused by long-time vibration in practical engineering; Secondly, the observer based on sliding mode variable structure is designed to obtain real-time estimation of unknown interference terms using the equivalent control principle of sliding mode variable structure, which can be further used to calculate the observed values of unknown interference terms; Finally, a control algorithm based on sliding mode observer is proposed. The algorithm inputs complex unknown interference observed values into the sliding mode controller (SMC) as feedback, thereby allowing the observed values to accurately track nonlinear unknown disturbance and weaken the vibration. Stimulation and experimental verification have proven the effectiveness and feasibility of the proposed method.

Investigating the car-body vibration of high-speed trains under different operating conditions with full-scale tests

An in-depth understanding of car-body vibration characteristics is the key to developing more reasonable operational safety and discomfort evaluation indicators. However, few scholars or research institutions have focused on this topic, and the car-body vibration characteristics that are caused by different complex aerodynamic factors are not clear. Therefore, in this study, different train car-body vibrations under different conditions were investigated using full-scale tests from 2014 to 2016. The results revealed that the car-body vibration for different aerodynamic conditions was mainly low-frequency rolling and traversing motion below 1 Hz, and the primary frequency was close to the car-body lower-centre rolling natural frequency. In addition, the evaluations of the train operational safety and the vibrational comfort could be considered coupled under strong wind conditions. There was a strong line relationship between the car-body roll angle and the train overturning coefficient under strong wind conditions, hence, predicting the train’s overturning risk by the car-body roll angle was feasible.

Study on line Vibration Characteristics of Equipment for Electric Multiple Units

The rigid-flexible vibration of high-speed train will cause the violent movement of equipment. This paper first introduced the high-speed EMU equipment and the theory of mass tuning vibration absorption. Then according to the test data, the vibration response of the bogie frame and the vibration response of the equipment, and the vibration response of the equipment under different lines are analyzed. The results show that the lateral vibration frequency of the frame is 4.5 Hz in normal section, and the lateral vibration frequency of the frame is 7.4 Hz in hunting excitation section. During the normal vibration line, the vibration of the equipment is significantly larger than that of the carbody, the vibration characteristics of the frequency domain of the equipment is mainly high-frequency magnetic vibration, the high-frequency vibration of the equipment above 15Hz is not transmitted to the carbody. When the running speed is increased, the vibration of the equipment is enhanced, and the line condition also has an important influence on the vibration of the equipment.

Kernel Density Estimation Based Gaussian and Non-Gaussian Random Vibration Data Induction for High-Speed Train Equipment

Because general statistics tolerance is not applicable to the induction of non-Gaussian vibration data and the methods for converting non-Gaussian data into Gaussian data are not always effective and can increase the estimation error, a novel kernel density estimation method in which induction is carried out on power spectral density data for the measured vibration of high-speed trains is proposed in this paper. First, data belonging to the same population of power spectral density are merged into the same feature sample. Then, the probability density function of all power spectral density values at the first frequency point is calculated through the kernel density estimation method, and the upper-limit estimate of all power spectral density values under the set quantile is obtained. This process is repeated, and the upper limit values of the power spectral density values at all frequency points can be obtained to convert the measured acceleration data to the acceleration power spectral density spectrum of the vibration test. Engineering examples are used to verify the proposed method. For the same Gaussian power spectral density data, the relative error between the root mean squares of the power spectral density spectrum obtained from induction by the kernel density estimation method and the statistics tolerance is 0.155% ~1.55%; for the non-Gaussian power spectral density data, the acceleration power spectral density spectrum of the non-Gaussian vibration can be obtained with the induction by the kernel density estimation method. The proposed kernel density estimation method satisfies the induction requirements for the measured Gaussian and non-Gaussian vibration data of high-speed trains with two different distributions, and its induction results have very good universality and estimation accuracy.

Effect of Long-Term Bridge Deformations on Safe Operation of High-Speed Railway and Vibration of Vehicle–Bridge Coupled System

Operation safety of high-speed trains is dependent on their vibration characteristics, which vary with bridge deformation. This paper studies the influence of bridge pier settlement and girder creep camber, which are two typical types of long-term bridge deformation, on the vibration of high-speed trains. To this end, an analytical approach is presented to link the bridge deformation with railway track deformation; the track deformation is used to analyze the vibration of the CRH2 high-speed train in China. The vibration analysis results are validated using the in-situ measurement data. The present study shows that bridge pier settlement greatly affects the vertical acceleration, derailment coefficient and wheel unloading rate of the high-speed train; incorporating bridge girder camber aggravates the vibration of the train–bridge system. The threshold of bridge pier settlement is suggested to be 11.1[Formula: see text]mm for trains moving at 350[Formula: see text]km/h with regard to the code-specified vibration limit. This study has significant implications for the design and operation of high-speed railways.

An analysis of the self-excited torsional vibration of high-speed train drive system

In this paper, a simplified torsional vibration model of drive system with three degrees of freedom is established, and the elasticity of wheelset is considered. In addition to the same wheel-rail adhesion condition for the two wheels, the different wheel-rail adhesion conditions for the two wheels have been considered for the first time, and the mechanism of the vibration forms is explained from the viewpoint of energy. The nonlinear system is linearized at the origin (equilibrium position), and the critical stability curve of the linearized system is drawn according to the eigenvalues of the linearized system in the state space. The results show that the vibration forms of the system are mainly determined by the relationships between the average creep rate and the critical creep rate of the wheel driven directly by motors. When the resistance moments do positive work on the system, they input energy to the system, and the responses do not tend to the origin and produce self-excited vibration. When the resistance moments do negative work on the system, they dissipate energy to system, and the responses tend to the origin. For the linearized system at the origin, the system is more stable at the origin when following factors occur, a gentler negative slope of the adhesion curve, a faster speed, a lighter wheel load, and a larger the moment of inertia of wheels.

Study of the Influence of Train Vibration Loading on Adjacent Damaged Tunnel

In this study, the effect of the high‐speed train vibration loading on an adjacent damaged tunnel is investigated. Three sets are established to study the effects of the different vibration loadings on the tunnel lining considering the vertical excitation force of the CRH (China Railway High‐speed) train. An expression of excitation force for the train vibration loading is applied to simulate the interaction force between wheel and rail, which is set with high‐, medium‐, and low‐frequency responses, and reflects the influences of driving comfort, additional dynamic load, and rail corrugations. The eigenvalue analysis and spring damping absorbing boundary are applied in the numerical simulation. In addition, a quantitative criterion is selected as the allowable vibration peak velocity for the cracked structure. The analysis of the vibration velocity, dynamic deformation, and acceleration of the cracking region show that the secondary lining of this damaged tunnel in set 1 basically has a higher vibration response than that in set 2 for the closer running track. The most adverse working condition with the greatest impact on the lining structure is that two CRH trains simultaneously passing through the cross section in set 3.

Measurements of car-body lateral vibration induced by high-speed trains negotiating complex terrain sections under strong wind conditions

ABSTRACTAssessment of the vibration of high-speed trains negotiating complex sections of terrain under strong wind conditions is very important for research into the operation safety and comfort of passengers on high-speed trains. To assess the vibration of high-speed trains negotiating complex sections of terrain under strong wind conditions, we performed a field measurement when the train passes through typical sections of complex terrain along the Lanzhou–Xinjiang high-speed railway in China. We selected the lateral vibration conditions, including the roll angle and lateral displacement of car-body gravity centre through two typical representative sections (embankment–tunnel–embankment and embankment–rectangular transition–cutting) for analysis. The results show that the severe car-swaying phenomenon occurs when the high-speed train moves through the test section, and the car-body lateral vibration characteristic is related significantly to the state of the terrain and topography along the railway. The main causes for this car-swaying phenomenon may be the transitions between different windproof structures, and the greater the scale of the transition region between different windproof structures or landform changes, the more obvious the car-swaying phenomenon becomes. The lateral vibration of the car-body is relatively steady when the train is running through terrain with minor changes in topography, such as the windbreak installed on the bridge and embankment, but the tail car sways more violently than the head car. When the vehicle runs from the windbreak installed on the embankment into the tunnel (or in the opposite direction), the tail car sways more intensely than the head car, and the head car runs relatively stable in the tunnel.

Effect of Expansion Wave Generated by Train Tail Entering into Tunnel on Lateral Vibration of High-Speed Train

Effect of Expansion Wave Generated by Train Tail Entering into Tunnel on Lateral Vibration of High-Speed Train

Analysis on the Impact of the Constitutive Model of Trains Vibration in Shield Tunnel

In this paper, with the in-situ engineering project Shiziyang tunnel of Guangzhou-Shenzhen Railway, under the disturbance of high-speed train vibration load, the shield tunnels dynamic response and foundations sand liquefying phenomenon are studied ,where they are mainly located in saturated and soft soil. Due to the tunnel going through the paralic deposited silt layer, silty soil, alluvial clay layer and the layer of fine sand or coarse sand layer, under the condition that enduring a long time of high-speed train running, which may easily lead to the foundation liquefaction and asymmetric settlement. At the entrance of the tunnel, with the poor geological conditions and weak cladding, which can easily induce sliding and collapse, where the geological conditions of this part is the most unfavorable place. Through numerical simulations, the main factor the constitutive model is explored, which may affect the single high-speed train loads on the vibration response of the train in shield tunnel and the law of accumulation and dissipation for pore water pressure.